The Teams window has several main screen elements that you can use, no matter which view you’re in.
A
App Bar: This is where you can switch between the six main views—Activity, Chat, Teams, Calendar, Calls, and Files. You can also add other apps to Teams and access them here.
B
Content Pane: This is where your chat conversation with your contacts is displayed.
C
List Pane: Depending on which view you're in, this will display a list of teams, chats, contacts, or other categories of information.
D
Command Box: This is where you can search for a contact, team, meeting, or anything else in Teams.